Center friction for clocks and watches



Dec. 31, 1929. w. E. PORTER 1,741,952

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I I IC Patented Dec. 31, 1929 UNITED STATES PATENT OFFICE WILSON E.PORTER, OF NEW HAVEN, CONNECTICUT, ASSIGNOR TO THE NEW HAVEN CLOCK CO.,OF NEW HAVEN, CONNECTICUT, A CORPORATION CENTER FRICTION FOR CLOCKS ANDWATCHES Application filed December My invention relates to animprovement in center-frictions for clocks and watches, the object beingto provide, at a low cost for manufacture, simple and reliable means forfrictionally coupling the hands of a clock or watch with thedriving-train thereof, so as to permit the hands to be turnedindependently of the train for purposes of setting, whereby the springfriction-washers heretofore employed for frictionally coupling the handsof a clock or watch with the drivingtrain thereof are dispensed with,and the number of parts in a given time-mechanism reduced.

WVith these ends in view, my invention con sists in initially bendingthe center-arbor of a time-mechanism so as to place its respective endsout of line, so that when straightened out, due to its installation inthe concentric passage of a member of the driving-train of atime-mechanism, sufiicient friction will be developed between it and thesaid drivingmember to cause the arbor to normally revolve with the saidmember, but free to be turned in either direction independently thereof.

My invention further consists in a centerfriction for clocks andwatches, characterized as above, and having certain details ofconstruction as will be hereinafter described and particularly recitedin the claims.

In the accompanying drawings:

Fig. 1 is a broken view in central section of a watch-movement embodyingmy improved center-friction; and

Fig. 2 is a detached view in elevation of a center-arbor forming anelement ofmy improvement.

In carrying out my invention, as herein shown, I employ a center-arbor 5which is preferably reduced in diameter, as at 6, near its rear end, tobetter enable its respective ends to be bent slightly out of line. Suchan arbor, initially so bent, is driven into the con centric passage 7 ofthe center-pinion 8 of the time-train of any standard watch or clockwith enough force to substantially straighten it out and thus developsufficient friction between it and the walls of the said passage tofrictionally couple them with the coherence Serial No. 236,959.

required to cause the arbor to rotate with the pinion. under the normalrunning conditions of the time-train, so that the arbor will be driventhereby.

As shown, the passage 7,in which the center-arbor 5 is installed, isslightly greater in diameter than the diameter of the arbor, so that,while the arbor, as substantially straightened, as described, as anincident of its installation in the said passage, makes sufficientcontact with the walls thereof for the development of thefriction-coupling required for driving the arbor, it is not boundtherein, so that while the arbor will normally be driven by thecenter-pinion, which, as uspanion hour-hand 12 is mounted, as usual,upon a hub or sleeve 13 carried by an hourwheel 14 mounted upon andfreely turning independently of the center-arbor which passes throughthem. A minute-wheel pinion 15, fixed upon the said arbor, so as torotate therewith, meshes into a wheel 16 of the dial-train, this wheelcarrying a pinion 17 meshing into and driving the hour-wheel 14:aforesaid. As shown, the center-pinion 8 is reduced at its front andrear ends respectively, having bearing in the front and rearmovement-plates 18 and 19.

Preferably and as shown, the arbor is pro vided with the reduced portion6 to facilitate bending it, though this is not imperative.

It will be clear from the foregoing that under my invention thefriction-washers ordinarily employed for frictionally coupling thecenter-arbors and driving-trains of timemovements are dispensed with andthe centerpinion itself caused to discharge their func tion, whereby thenumber of parts is reduced and a great saving secured without any lossforward end 11 of the arbor, while its comof effectiveness. My inventionis particularly adapted to small watch-movements where economy of spaceis of vital importance, and in which the parts are so minute as to maketheir production, assembly and installation a delicate and expensiveoperation.

I claim:

1. The combination with a member of the driving-train of a clock orwatch, the said member having a concentric passage formed therein, of acylindrical center-arbor initially bent bodily so as to place itsrespective ends out of line, whereby, when installed in the saidpassage, it is sufiiciently straightened thereby to develop the frictionrequired for normally yieldingly coupling the said arbor anddriving-member with a capacity for the independent turning of the arborfor setting the mechanism.

2. The combination with a member of the driving-train of a clock orwatch, the said member having a concentric passage formed therein, of acylindrical center-arbor formed between its ends with a reduced portionand initially bent bodily at such reduced portion to place its ends outof line, whereby, when installed in the said passage, it is suflicientlystraightened thereby to develop the friction required for normallyyieldingly coupling the said arbor and drivinganember with a capacityfor the independent turning of the arbor for setting the mechanism.

In testimony whereof, I have signed this specification,

WILSON E. PORTER.

